The present invention relates to a printer using water-based ink and a printing plate used in said printer.
The Official Gazette of Japanese Patent Laid-Open NO. 310101/1996 discloses that a patterned water-based ink layer is formed by feeding water-based ink to a plate having an ink repellent substance in a non-printing area, and the patterned water-based ink layer is then transferred to the object to be printed. The Official Gazette of Japanese Patent Laid-Open NO. 228066/1995 discloses that a non-water-soluble zinc compound powder provided with hydrophilic treatment is used as a component of an image receiving layer for a direct plotting offset printing plate.
A gravure printing printer or offset printing printer provides high-speed volume printing of advertisement fliers and books having identical images. However, such a machine has problems when handling images for a low volume production with a wide variety of types; namely, much time and cost are required to form the plate, and the plate cannot be recovered. An innovative idea, including the invention of a printing method and a printer allowing recovery of a plate, has been required to achieve effective production of printed matter in volumes of hundreds to thousands of copies required.
The object of the present invention is to provide a printer which ensures easy formation of a plate and recovery of the plate, and to a printing plate.
The inventors of the present invention have studied many types of printing methods and have come to the conclusion that the above object can be achieved if a once used plate can be recovered, so that the plate forming process can be reduced. Thus, they have studied various methods of facilitating plate formation, and have found that it is possible to manufacture a system which can achieve the above object by using water-based ink and a super-ink-repellent plate, and by utilizing a water soluble material for formation of a latent image.
The following is a specific description of our invention: The term xe2x80x9csuper-ink-repellent surfacexe2x80x9d appearing in this Specification means that the surface does not allow deposition of a drop of ink equal to or greater in size than the minimum size of a dot in the printing process. The minimum dot size of the printer used in the embodiments was 10 microns. In this Specification, this surface is defined as a surface which repels a drop of ink having a size greater than that, namely, 10 microns or more, when said surface is brought in contact with said ink. Furthermore, the term xe2x80x9cwater soluble materialxe2x80x9d used in this Specification is defined as a substance which is 100% infinitely diluted with water at normal temperature and deposits on the super-ink-repellent surface.
(1) A printing plate used in a printer to form an image using water-based ink is characterized in that, prior to formation of a latent image, the surface forming the latent image exhibits super-ink-repellency to the used ink; said printing plate allows a water soluble material forming the latent image to be deposited thereon; the latent image can be formed by allowing said water soluble material deposited on said printing plate surface; and said printing plate can be recovered as a plate which allows a new latent image to be formed by washing said printing plate with water and drying it, upon completion of ensuing processes of development and transfer.
(2) A printer comprises at least a plate; a mechanism forming a latent image on said plate; a mechanism allowing ink to be deposited and developed on said plate where the latent image is formed; and a mechanism to transfer said developed image onto paper; and said ink is water-based ink. The printer is characterized in that prior to formation of a latent image, the surface of the plate exhibits super-ink-repellency to the used ink; said printing plate allows a water soluble material forming the latent image to be deposited thereon; the latent image can be formed by allowing said water soluble material deposited on said printing plate surface on said plate surface; and a mechanism is provided to permit said printing plate to be recovered as a plate which allows a new latent image to be formed thereon upon completion of ensuing processes of development and transfer. The mechanism contains at least a device to remove ink deposited on said plate and a device to dry said plate.
(3) The printer is characterized in that a mechanism to heat said plate or transfer mechanism is provided inside said plate and transfer mechanism.
(4) The printer is characterized in that a mechanism to suck waste water generated in said washing step.